Added 10MiB recv limit for WS frames, also a small nit - Added WS_MAX_RECV_FRAME_SZ, if a received frame exceeds this limit (10 MiB), error out. This is a DoS prevention measure. - Also redid the unmasking code in get_ws_frame(), to avoid assumptions about the size of an unsigned int and some casting, and avoid memcpy(), just use the mask bytes from the buffer that are already there to unmask.